Below is a very simple look into how a website works, and what each component of your website does. Please keep in mind, this is a very simple overview. Incorporated below is your domain name, hosting and actual website, along with the order they are used in a typical situation.
Website Browser of a Computer
This is the beginning of the process. This is where a customer or person either directly enters your domain name, or clicks on a link to your domain name in their internet browser. An example of an internet browser is Internet Explorer. This triggers the Next Step.
Domain Name Server (DNS) Lookup
Once an Internet browser has been supplied a web address to go to (Above), it then looks up that domain name in a massive domain name database and gets the location (Unique IP Address) of the server where it is stored. This server is your hosting (Below).
Web Server / Hosting
Your server (Hosting) is a type of computer that is available to the public 24/7. It is responsible for saving all of your websites information and databases. Once it receives a request, its other job is to send the called upon information back to the user (Below).
File and Information Retrieval
So, someone has called up your web address, in a browser, and the DNS has pointed it to your hosting, now, as part of the hosting, we need to send the called information back to the user. Each page of your website has different information on it, and if no specific page was called, the server will send back the 'Home' pages information. This information usually consists of the websites text and images. Then, the users internet browser, readt the sent information, and displays your website as described it your websites code. This code is your actual website, as designed by a designer.